Hannum Prospect, Fairhaven Mining District, Northwest Arctic Borough, Alaska, USAi

Regional Level Types
Hannum Prospect	Prospect
Fairhaven Mining District	Mining District
Northwest Arctic Borough	Borough
Alaska	State
USA	Country

Location: The Hannum prospect is on the west bank of the headwater part of Hannum Creek, 1,000 feet upstream of the confluence with Cunningham Creek. Hannum Creek is a north tributary to Inmachuk River. This is locality 8 of Cobb (1972; MF 417; 1975; OFR 75-429).
Geology: A poorly exposed, interlayered metasedimentary schist and dolomitic marble sequence strikes northwest and dips moderately (15 to 65 degrees) to the north in the general area. Part of this meatsedimentary sequence is siliceous and described as quartzite (Herried, 1966). Herried considers the quartzite here and at Harrys Creek (BN055), 4,000 feet to the northwest, to be replacements of marble (silicified marble). Hudson and others (1977) described outcrops of the silica-rich rock on Harrys Creek as siliceous schist. The frozen ground in the Hannum prospect area has handicapped efforts to expose bedrock (Mulligan, 1965; Herreid, 1966). Although dozer trenching along the west bank of Hannum Creek is extensive (totalling about 1,500 feet in at least 6 different trenches) mineralization was only locally exposed; a 30 foot-wide gossan zone within marble is exposed in one trench. Mineralization is apparently pods and stringers of sulfides (primarily galena, sphalerite and pyrite) in silica-rich rock. An assay of a 6-foot wide siliceous zone contained 0.05 % Cu, 0.38 % Zn, and 0.12 % Pb, and nil amounts of Ag and Au (Herried, 1966, Table 1). Soil samples collected upslope 125 to 375 feet to the west, contained anomalous lead and zinc values (to greater than 1,000 ppm); soil samples in this prospect area commonly contain more anomalous zinc than lead values (Herreid, 1966, Table 2). Although continuity of mineralization over the 4,000 feet of strike length between the Hannum prospect and Harrys Creek (BN055) to the west is possible, it has not been demonstrated.
Workings: Dozer trenching along the west bank of Hannum Creek is extensive; it totals about 1,500 feet in at least 6 different trenches. Mineralization was only locally exposed; a 30 foot-wide gossan zone within marble is exposed in one trench.
Age: The deposit may be epigenetic and younger than the host metasedimentary rocks. Epigenetic deposits on Seward Peninsula are primarily Cretaceous in age, a time of significant regional metamorphism and granitic plutonism. The Inmachuk River and many of its tributaries, including Cunningham and Hannum Creeks, contain signficant placer gold deposits. Some lode gold deposits on southern Seward Peninsula are mid-Cretaceous in age (see Midnight Mountain, BN047). If the deposit is stratiform, it may be similar in age to its host sedimentary rocks. The protoliths for the metasedimentary rocks in this area are lower Paleozoic in age (Till and others, 1986).
Alteration: Development of silica-rich rock is characteristic. The deposit is deeply weathered and oxidized.

Commodities (Major) - Pb, Zn; (Minor) - As, Ba
Development Status: No
Deposit Model: Sulfide-bearing pods and disseminations in silica-rich metasedimentary rocks; it

Other Databases

Link to USGS - Alaska:	BN056

Other Regions, Features and Areas containing this locality

References